Liquid circulation system and liquid cooling system therewith

ABSTRACT

A pump equipped with an impeller having a plurality of vanes is installed through a packing at an opening section formed on a wall surface of one of components in a liquid circulation passage, such as a radiator so that the impeller of the pump section may be disposed herein. Inside the component, there is provided a partition plate formed with a hole at such a position as to face the center of the impeller. A port is provided between a wall surface having the opening section and the partition plate. By the rotation of the impeller, a liquid flow is produced toward the port from the inside of the compartment through the hole.

INCORPORATION BY REFERENCE

The present application claims priority from Japanese application JP2004-214574 filed on Jul. 22, 2004, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

The invention relates to a liquid circulation system for circulating liquid using a pump and a liquid cooling system therewith, and more particularly to a liquid circulation system equipped with a pump capable of being miniaturized and a mounting structure thereof, and a liquid cooling system therewith.

PRIOR ART

The increasing speed of a device and an integrated circuit used in a personal computer, a server or the like, especially a CPU has been recently much-needed, which has been increasing heating value.

The present mainstream of cooling a CPU is a direct air-cooling system for spraying cooling air to a heat sink by fixing the heat sink on the CPU and mounting a fan on it. However, cooling by means of the direct air-cooling system restricts a space around the CPU due to high-density conversion of an apparatus, as well as the size of the heat sink, thus restricting cooling capacity and fan size. To obtain high air volume, this needs to rotate a small-sized fan at a high speed, which leads to increasing noise.

For utilization of a large-sized heat sink and a large-sized fan with high efficiency, attempts have been made to apply a heat transport system such as a liquid cooling system. However, the conventional liquid cooling system is constituted of a larger amount of parts than an air cooling system, which causes difficult miniaturization and needs reduction in the number of parts and size.

As a related art capable of miniaturizing the liquid cooling system, for example, an art disclosed in JP-A-2004-92610 is known. This related art relates to miniaturization of a pump and uses a small-sized impeller.

As another related art, for example, an art disclosed in JP-A-2003-343492 is known. This related art, a centrifugal pump being slimmed, constitutes a pump from a slim impeller and a small-sized port.

As a further related art, an art disclosed in JP-A-2004-47921, which miniaturizes a liquid cooling system by integrating a pump with a cooling jacket, is used.

SUMMARY OF THE INVENTION

The foregoing related art disclosed in JP-A-2004-92610 has a problem that a small-sized impeller cannot increase a flow rate because efficiency is lower than that of a large-sized impeller. In the foregoing related art disclosed in JP-A-2003-343492, its centrifugal pump has a characteristic that its open flow rate is higher and static pressure is lower than that of one of other systems, for example, a piston pump. The related art using a small-diameter port has a problem that the flow rate of coolant becomes lower, especially in using coolant with high viscosity. Moreover, the art disclosed in JP-A-2004-47921 has a problem that the shape of a pump case must be specialized in accordance with the shape of an object to be cooled because part of a pump casing becomes a heat receiving surface, which leads to lost general versatility of a pump itself and difficult cost reduction by mass-production effect.

Any of the respective related arts relates to a liquid cooling system using a centrifugal pump. One of fundamental problems of the centrifugal pumps is that a liquid flow stops when air is mixed into an internal pump. The liquid flow stop is more apt to occur due to air mixing as the space of the internal pump is smaller.

A conventional liquid cooling system aimed at free maintenance has a problem of the permeability of coolant from a pump surface, namely, that coolant is lost while passing through a material constituting a pump case. This problem can be solved by using metal for a pump casing. However, if an impeller must be driven by magnetic force, metal cannot be, in practice, used for the case and polymer material is unavoidably used. A portion which is hardly associated with the magnetic force can use metal, which causes a problem that a cost increase occurs.

Accordingly, it is an object of the present invention to provide a liquid circulation system for circulating liquid using a pump and a liquid cooling system therewith, capable of solving the foregoing problems of conventional arts and the foregoing problem a centrifugal pump has, reducing the number of parts, and being miniaturized.

To achieve the aforementioned object, a liquid circulation system of the present invention, circulating liquid with a pump equipped with an impeller having a plurality of vanes, is structured as follows: the pump is installed through a liquid sealing mechanism on an opening section formed in a wall for a component in a liquid circulation passage so that the impeller in the pump may be disposed inside the component, a partition plate formed with a hole at such a position as to face the center of the impeller, a port is formed between a wall surface having the opening section and the partition plate, thereby generating a liquid flow in the direction of the port through the hole from the inside of the component by the rotation of the impeller.

In the foregoing structure, the pump equipped with the impeller comprises a shaft inserting through the center of the rotating shaft of the impeller, a wall for vertically supporting the shaft, permanent magnets mounted on the impeller, and electromagnets, which are respectively fitted on a surface on the opposite side to the impeller, sandwiching the wall to drive the rotation of the impeller.

The aforementioned object can be achieved by using the foregoing liquid circulating system in addition to a liquid cooling system having a component for performing heat exchange, a component for holding coolant, and a component which is brought into contact with a heat generating member and cools the heat generating member.

Accordingly, the present invention can miniaturize a liquid circulation system and minimize pressure drop loss in piping.

Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an example of a configuration of an electronic device to which a liquid cooling system is applied according to an embodiment of the present invention;

FIG. 2 is a sectional view illustrating a configuration of a pump section used according to one embodiment of the present invention;

FIG. 3 is an explanatory view illustrating shapes of an impeller and vanes constituting a pump section, arrangement of electromagnets, and arrangement of permanent magnets;

FIG. 4 is a sectional view illustrating a configuration of a liquid cooling system according to a first embodiment of the present invention;

FIG. 5 is a sectional view illustrating a configuration of a liquid cooling system according to a second embodiment;

FIG. 6 is a sectional view illustrating a configuration of a liquid cooling system according to a third embodiment; and

FIG. 7 is a sectional view illustrating another configuration of a pump section used according to an embodiment of the present invention.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. However, this does not limit the present invention.

PREFERRED EMBODIMENTS OF THE INVENTION First Embodiment

FIG. 1 is a perspective view illustrating an example of a configuration of an electronic device to which a liquid cooling system is applied according to an embodiment of the present invention, where a reference symbol 101 is a casing, a reference symbol 102 is a mother board, a reference symbol 103 is a CPU, a reference symbol 104 is a chip set, a reference symbol 105 is a memory, a reference symbol 106 is a PCI board, a reference symbol 107 is a HDD, a reference symbol 108 is a CD-ROM, a reference symbol 109 is FDD, a reference symbol 110 is a power supply unit, reference symbols 111 a, 111 b are jackets, a reference symbol 112 is a radiator, a reference symbol 113 is a tank section, a reference symbol 114 is a pump section, a reference symbol 115 is a fan, and reference symbols 116 to 118 are tubes. The electronic device illustrated in FIG. 1 is an approx. 44.4 high slim server, that is, a 1U server as an example.

The server as the electronic device illustrated in FIG. 1 is constituted by mounting the CPU 103, the chip set 104, the memory 105, and the PCI board 106 on the mother board 102 provided inside the casing 101. As an external storage, the HDD 107, the CD-ROM 108, and the FDD 109 are mounted ahead, and the power supply unit 110 is mounted on the rear side of the casing 101.

The liquid cooling system provided on the server is constituted of the radiator 112 fitted with the fan 115, the tank section 113 provided at its one end, the pump section 114 provided at the other end, jackets 111 a, 111 b mounted on the two CPUs 103, the tube 118 for making a connection between the jackets, the tube 116 for connecting the jacket 111 b with the tank section 113, the tube 117 for connecting the jacket 111 a with the pump section 114, and coolant circulating inside the tube 117. As the coolant, it is sufficient to use a mixture of ethylene glycol or propylene glycol and water. A mixture prepared by mixing ethylene glycol or propylene glycol with water at the rate of approx. 30% to water may be used.

The jackets 111 a and 111 b of the liquid cooling system are respectively mounted on the CPUs 103 and absorb heat from the CPUs 103. Specifically, the jackets 111 a, 111 b are formed out of metal with high heat transfer such as copper or aluminum. Contact surfaces between the jackets 111 a, 111 b and the CPU 103 are crimped with thermal compound, silicon rubber with high heat transfer or the like sandwiched therebetween so that the heat generated by the CPU 103 may be transferred to the jacket with high efficiency. The coolant passes through the inside of each of the jackets 111 a, 111 b, and heat from the CPU 103 is transferred to the coolant and carried to the radiator 112.

The radiator 112 for cooling coolant is provided with the tank section 113 for storing coolant and the pump section 114 for generating a liquid flow. The configuration of the radiator 112 having the pump section 114 is described below. The radiator 112 is attached with the fan 115, and wind is sent to the radiator 112.

As described earlier, piping of the liquid cooling system is formed out of the tubes 116 to 118. The tube 116 connects the jacket 111 b with the tank section 113, the tube 117 connects the pump section 114 with the jacket 111 a, and the tube 118 connects the jacket 111 a with the jacket 111 b.

The order of a coolant flow according to this embodiment is as follows: pump section 114→jacket 111 a→jacket 111 b→tank section 113→radiator 112→pump section 114 (again). By passing the coolant cooled by the radiator 112 through the pump section 114 in this way, the pump section 114 can be prevented from being overheated.

FIG. 2 is a sectional view illustrating a configuration of a pump section 114 in FIG. 1, FIG. 3 is an explanatory view illustrating shapes of an impeller and vanes constituting a pump section 114, arrangement of electromagnets, and arrangement of permanent magnets, and FIG. 4 is a sectional view illustrating a configuration of a liquid cooling system according to an embodiment. The liquid cooling system illustrated in FIG. 4 is constituted by installing the pump section 114 on the radiator 112. FIGS. 2 to 4, a reference symbol 201 is an impeller, a reference symbol 202 is a permanent magnet, a reference symbol 203 is a vane, a reference symbol 204 is a bearing, a reference symbol 205 is a shaft, a reference symbol 206 is a washer, a reference symbol 207 is a bottom wall, a reference symbol 208 is a stopper, a reference symbol 209 is a bent section, a reference symbol 210 is a packing, a reference symbol 211 is an electromagnet, a reference symbol 301 is a passage, a reference symbol 302 is a fin, a reference symbol 303 is a wall surface, a reference symbol 304 is a hole, a reference symbol 305 is a partition plate, a reference symbol 306 is a port and a reference symbol 307 is a screw, and other symbols are the same as in FIG. 1.

The pump section 114 is constituted as a centrifugal pump formed integrally with a motor and, as illustrated in FIG. 2, the pump section 114 consists of the impeller 201 having the permanent magnets 202 and the vane 203, the bottom wall 207 for supporting the impeller 201, and the electromagnets 211 mounted on the bottom wall 207. The impeller 201 includes a plurality of permanent magnets 202 as illustrated in FIG. 3 (a) and FIG. 3 (c), and the plurality of vanes 203. The bearing 204 is in the center of the impeller 201, and the shaft 205 penetrates through the bearing 204. The shaft 205 which penetrates through the inside of the bearing 204 is formed with the two washers 206 at the top and bottom thereof. The bottom washer 206 has a notched shape and is embedded to be fixed in the bottom wall 207. On the other hand, the top washer 206 is constituted so as not to be rotated by the bent section 209 of the stopper 208.

The bearing 204, the shaft 205, and the washer 206 may be formed out of a material with excellent wear resistance, such as ceramic. The bearing 204 is set so as to be brought into contact with the top and bottom washers 206, therefore contact surfaces thereof rub with each other while the impeller 201 is rotating, however, these parts have excellent wear resistance, thus exhibiting long service life.

On the bottom wall 207 supporting the shaft, the packing 210 is provided at a surface on the same side as the surface on which the impeller 201 is installed, and electromagnets 211 are provided at the opposite surface. A motor for driving the rotation of the impeller 201 is formed out of the electromagnets 211 provided on the bottom plate 207 and the permanents magnets 202 provided on the impeller 201. The electromagnets 211 provided on the bottom plate 207, as illustrated in FIG. 3 (b), is constituted of a plurality of coils producing a magnetic force in such a direction as to vertically penetrate through the bottom wall 207, and the permanents magnets 202 provided on the impeller 201 similarly, as shown in FIG. 3 (c), is a plurality of permanents magnets for generating magnetic forces in a direction perpendicular to the bottom wall 207, where the adjacent magnets are arranged so as to have reversed polarity each other.

The motor for rotating the impeller 201 is constituted of the permanent magnets 202 facing through the bottom plate 207 and the electromagnets 211, therefore the bottom plate 207 requires use of a member made of a material capable of penetrating a magnetic force, and it may be formed out of hard plastic or the like.

The pump section 114 does not have a port or a casing for ensuring water tightness, which a conventional pump uses. The pump section 114, being not used solely with only a structure illustrated in FIG. 2, can exhibit a function serving as a pump only by being installed other radiator, tank or the like. Referring now to FIG. 4, there is described an example of a configuration in which the pump section 114 illustrated in FIG. 2 is installed on the radiator 112. An arrow indicated in FIG. 4 shows a flow of coolant.

The radiator 112 is constituted of piping forming a plurality of passages 301 and a great number of fins 302 mounted thereon. On the left and right thereof, the tank section 113 and the pump section 114 are installed, and each of them is connected with the passages 301. The plurality of passages 301 are parallel, and the fins 302 are thermally jointed to the passages 301, so that the heat of the coolant running through the passages 301 is transmitted to the fins 302. The passages 301 and the fins 302 are formed so that the wind from the fan 115 may hit, where the heat of the coolant is cooled. The radiator section 112 is formed out of copper or aluminum with high thermal conductivity.

The tank section 113 stores a fixed amount of coolant to ensure long-term reliability of the liquid cooling system. The liquid cooling system includes some portions using a member causing water permeation such as a polymer member, from which water permeation occurs, thus gradually reducing liquid amount. The tank section generally requires to maintain a sufficient amount of liquid for endurance against long-term use, however, this embodiment requires a smaller amount of polymer material usage, thus causing reduction in water permeation amount. Therefore, a smaller-size tank than a conventional one may be used.

The side on which the pump section 114 of the radiator 112 is installed is constituted of the wall surface 303 with the hole, in which the pump section 114 is assembled. The vanes 203 of the pump section 114 are positioned on the inner side of the wall surface 303. The pump section 114 is fixed on the wall surface 303 by a screw 307. Between the wall surface 303 and the bottom wall 207 of the pump section 114, the packing 210 exists, thus causing no liquid leakage. On the inside of the wall surface 303 with holes of the radiator 112, there is provided a partition plate 305 with the hole 304 at a position approaching the impeller 201 of the pump section 114 installed on the wall surface 303 without contacting the impeller 201. The hole 304 is formed so as to face the central portion of the impeller 201. On the passage 301 side of the hole 304, a room for guiding coolant collected from the plurality of passages 301 to the hole 304. The port 306 is provided on the impeller side of the space partitioned by the partition plate 305, that is, between the partition plate 305 and the wall surface 303.

With the foregoing configuration, by driving the rotation of the impeller, the coolant passing through the passage 301 of the radiator 112 is sucked from the hole 304 formed on the partition plate 305 and flows out of the port 306. The pump section 114 operates under a state assembled in the radiator 112 and can eliminate piping for connecting the pump section with the radiator, thus miniaturizing the liquid cooling system and further eliminating pressure loss due to piping. Specifically, a portion sucking liquid by negative pressure resulting from the rotation of the vanes 203 of the impeller 201 is the hole 304 on the partition plate 305. The hole 304, having no restrictions on its diameter, can be significantly enlarged, thus almost neglecting pressure loss.

In a conventional way, the pump section and the tank are structured so as to be connected with each other through piping. If large-diameter piping is used, a pump port itself is enlarged, thus upsizing the pump. If the pump needs downsizing, the port must be unavoidably reduced in diameter, thus causing lowering of flow rate due to pressure loss.

In a conventional way, water permeation occurs from the whole pump casing, while the pump section 114 according to this embodiment is half immersed in the metallic radiator 112, therefore water permeation from the pump section 114 is limited to only a surface of the bottom wall 207. The bottom wall 207 has a surface area not larger than the half of a conventional pump casing, thus achieving water permeation amount not larger than the half of a conventional one.

This embodiment can use the hole on the wall surface 303 installed with the pump section 114 as those for filling the liquid cooling system with liquid, and the pump section 114 as its lid. The hole on the wall surface 303 can facilitate filling with liquid because the hole is much larger in diameter than piping.

In this embodiment, a case where the tank section 113 is installed on the radiator 112 is described, however, the present invention may individually constitute the tank section 113 as the radiator 112 for connection with piping.

Second Embodiment

FIG. 5 is a sectional view illustrating a configuration of a liquid cooling system according to a second embodiment. Referring now to FIG. 5, the liquid cooling system according to this embodiment is described below. The liquid cooling system illustrated in FIG. 5 is constructed by installing a pump section on an independent tank section. In FIG. 5, a reference symbol 401 is a tank, reference symbols 402, 403 are ports, a reference symbol 404 is a wall surface, a reference symbol 405 is a hole, and a reference symbol 406 is a partition plate. Other symbols are the same as in FIGS. 1 to 4. An arrow indicated in FIG. 5 shows a flow of coolant.

In FIG. 5, the tank 401 is made of metal, the bottom surface of the tank 401 has the holed wall surface 404 for mounting the pump section 114 thereon, where the pump section 114 is assembled. The vanes 203 of the pump section 114 are positioned inside the wall surface 404. The pump section 114 is fixed on the wall surface 404 by the screw 307. Between the wall surface 404 and the bottom wall 207 of the pump section 114, the packing 210 is intervened, which prevents liquid from leaking. Inside the holed wall surface 404 of the tank 401, the partition plate 406 with the hole 405 is provided at a such a close position as to come into no contact with the impeller 201 of the pump section 114 installed on the wall surface 404. The hole 405 is formed so as to face the central portion of the impeller 201, and is open directly to the coolant in the tank. On the impeller side of a space partitioned by the partition plate 406, that is, between the partition plate 406 and the wall surface 404, the outlet port 403 for coolant is formed and, on the top of the tank 401, the inlet port 402 for coolant is formed.

With the foregoing configuration, when the rotation of the impeller 201 is driven, the coolant in the tank 401 is sucked from the hole 405 formed on the partition plate 406 and flows out of the outlet port 403. The pump section 114 operates in such a state as to be assembled in the tank 401, so that piping for connecting the pump section 114 with the tank 401 can be eliminated, thus achieving miniaturization of the liquid cooling system. Moreover, pressure loss due to piping can be also eliminated. Specifically, a portion which sucks liquid with negative pressure generated by the rotation of the vanes 203 of the impeller 201 is the hole 405 of the partition plate 406. The diameter of the hole 406, having no restrictions, can be set so as to be significantly large, thus setting pressure loss to a roughly negligible degree.

The coolant from the outlet port 403 flows in the order of the jacket and radiator and returns to the tank 401 from the inlet port 402, which are not shown in FIG. 5.

In a conventional way, the pump section and the tank are structured so as to be connected with each other through piping. If large-diameter piping is used, a pump port itself is enlarged, thus upsizing the pump. If the pump needs downsizing, the port must be unavoidably reduced in diameter, thus causing lowering of flow rate due to pressure loss.

In the conventional way, water permeation occurs at the whole pump casing. On the other hand, the pump section 114 according to this embodiment, being half submerged in the metallic tank 401, water permeation from the pump section 114 is restricted to only the surface of the bottom wall 207. The bottom wall 207, having a surface area not larger than a half as many as a conventional pump casing, can restrain water permeation to not larger than a half.

The hole on the wall surface 404 of the tank 401 installed with the pump section 114 can be used as a hole for filling the liquid cooling system with liquid, and the pump section 114 can be used as a lid. The hole on the wall surface 404 is far larger in diameter than piping, which can facilitate filling with liquid.

Moreover, a centrifugal pump generally has a problem of a liquid flow being stopped at the time of air mixing, which requires to discharge air at air mixing, but the conventional liquid cooling system, having high pressure loss because of piping connection, requires additional means of discharging air in the pump.

However, this embodiment can facilitate discharge of air in a pump. In other words, in the embodiment of the present invention illustrated in FIG. 5, if air gathers in the pump 114, that is, if air gathers around the vanes 203 of the impeller 201 surrounded by the partition plate 406 and the wall surface 404, it is sufficient only to stop the operation of the pump section 114, by which the air leaks upwards through the hole 405. In this way, this embodiment can facilitate discharge of air in the pump.

Stopping of a liquid flow occurs if air gathers around the vanes 203 of the impeller 201 and liquid amount in the space reduces. With this embodiment, a volume surrounding the vanes 203 of the impeller 201, that is, a space around the vanes 203 of the impeller 201 surrounded by the partition plate 406 inside the tank 401 is part of the tank 401, however, the size of the tank is generally larger than that of the pump, and this volume, namely, liquid amount is more than that of a conventional pump, therefore, the effect of air mixing is relieved, thus making it difficult to generate stopping of a liquid flow.

Third Embodiment

FIG. 6 is a sectional view illustrating a configuration of a liquid cooling system according to a third embodiment. Referring to the drawing, a liquid cooling system according to this embodiment is described. The liquid cooling system illustrated in FIG. 6 is constituted by integrating the pump section with a radiator. In FIG. 6, a reference symbol 501 is a jacket, reference symbols 502, 503 are ports, a reference symbol 504 is a wall surface, a reference symbol 505 is a hole, a reference symbol 506 is a duct, a reference symbol 507 is an opening section, and a reference symbol 508 is a heat sink. Other symbols are the same as in FIGS. 1 and 2. An arrow indicated in FIG. 6 shows a flow of coolant.

In FIG. 6, the jacket 501 is formed out of metal with excellent thermal conductivity, such as copper or aluminum. Onto the bottom surface of the jacket 501, a heat generating body to be cooled such as a CPU is jointed through thermal conductivity grease or the like. On the side of the jacket 501, there are provided an inlet port 502 and an outlet port 503 for coolant. Moreover, a top surface 504 is formed with the hole 505. In the hole 505 on the top surface 504, the pump section 114 is assembled, and the vanes 203 of an impeller are put inside the jacket. Although not illustrated, like other embodiments, the pump section 114 is fixed by screwing, and a packing is provided between the top surface 504 and the pump section 114, thus preventing liquid leakage from between the jacket 501 and the pump section 114.

The duct 506 is provided inside the jacket 501. The duct 506 is part of covered so as to include the pin-shaped heat sink 508 in a grid pattern. The duct 506 is connected with the inlet port 502 and is formed with the opening section 507. The opening section 507 is formed so as to face the central portion of the vane 203 of the impeller 201. That is, the duct 506 functions as piping from the inlet port 502 to the central portion of the vane 203 of the impeller 201. Therefore, when the vanes 203 of the impeller 201 are rotated, its central portion is kept at a negative pressure, so that the inlet port 502 functions as a suction opening. The heat sink 508 provided inside the jacket 501 is formed integrally with a surface in contact with a heat generating body, namely, the bottom surface of the jacket 501 and constituted so that the heat of the heat generating body may be transmitted. Hence, the heat transmitted to the heat sink 508 is cooled by bringing it into contact with coolant.

With the foregoing configuration, the liquid cooling system formed integrally with the jacket according to this embodiment provides higher thermal conductivity than a conventional jacket. Detailed description is made about the liquid cooling system as follows:

The coolant from the port 502 is sucked into the vanes 203 of the impeller 201 from the opening section 507 through the duct 506. Because the heat sink 508 exists in the duct 506 as well, cooling is performed to some degree at this point. The coolant passing through the vanes 203 of the impeller 201, while being agitating by the rotation of the vanes 203 of the impeller 201, is hurled against the heat sink 508 except a portion covered with the duct 506 and then flows out from the outlet port 503 toward the tank and the radiator not illustrated.

The thermal conductivity becomes higher as the flow rate of coolant is higher or coolant is more collision jet flow. In this embodiment, rotation of the vanes 203 of the impeller 201 produces a revolving liquid flow inside the jacket, so that a collision jet flow occurs, being hurled against the heat sink 508. Therefore, a jacket constituting a cooling system illustrated in FIG. 6 has a more rapid internal liquid flow than a conventional jacket through which coolant just passes and produces a collision jet flow, thus achieving high thermal conductivity and cooling performance.

In FIG. 6, the pump 114 operates under a state where the pump section 114 is assembled into the jacket 501. Accordingly, piping for connecting the pump can be eliminated, thus miniaturizing the liquid cooling system.

In this embodiment, the shape of the heat sink 508 is like a pin-shaped fin in a grid pattern, however, the fin is not limited to this shape, but may be of any type if an area in a contact with coolant is wide.

FIG. 7 is a sectional view illustrating another configuration of the pump section 114. In FIG. 7, a reference symbol 701 is an O-ring, and other symbols are the same as in FIG. 2.

The first to third embodiments describe that a packing is used to fill a clearance between a pump section and a component assembled with the pump section, however, as illustrated in FIG. 7, another way of sealing a clearance between a pump section and a component assembled with the pump section with an O-ring may be taken. A further another way, not illustrated herein, of a watertight structure by caulking may be used. Briefly speaking, it is sufficient to use a structure of filling a clearance between a pump section and a component assembled with the pump section.

A mounting structure of the permanent magnets 202 and the electromagnets 211 constituting the pump section 114 may be constituted, as illustrated in FIG. 7, by using the permanent magnets 202 of O-ring shape and embedding the electromagnets 211. Moreover, a permanent magnet may be used for the whole impeller 201. In short, it is sufficient to actualize a function of rotating the impeller 201.

In the first to third embodiments, the features of a pump section producing a liquid flow is that the pump section consists of an impeller, a shaft, a wall vertically supporting the shaft, a wall for vertically supporting the shaft, and electromagnets positioned on a surface opposite to the impeller sandwiching the wall, and that the pump section can be constituted without need for using a port nor a casing ensuring watertightness found in a conventional pump. In addition to the foregoing features, a wall surface of a component in a liquid circulation passage has an opening section larger than the impeller size of the pump section, the pump section is assembled into the opening section, a liquid sealing structure is provided between a wall of the pump section and a wall surface of the component, and a partition plate is provided inside the component to convert the pressure generated by rotating the impeller into a liquid flow in a desired direction.

The pump section operates under a state assembled into a component in the liquid circulation passage, which eliminates piping for connecting a pump found in a conventional way, thus miniaturizing a liquid circulation system.

A partition plate as means of converting the pressure generated by rotation of the impeller into a liquid flow in a desired direction has a hole at a position corresponding to the central portion of the impeller. The hole is made to serve as a port of a suction opening of the impeller, and an outlet port is provided on the impeller side of a space partitioned by the partition plate.

Such a configuration can eliminate pressure loss generated between a pump section and a component of a liquid circulation system, thus increasing the flow rate of coolant. Moreover, a port formed on a partition plate of the component of the liquid circulation system is made to serve as a port for the pump section, thereby miniaturizing the liquid circulation system.

Furthermore, a shaft passing through the center of a rotating shaft of an impeller is equipped with a stopper, therefore even the absence of a casing around the impeller can prevent the impeller from coming off the shaft.

A liquid cooling system constituted by use of the liquid circulation system can perform heat transport with a liquid flow by means of the liquid circulation system. As components assembled with the pump section, a radiator, a jacket and tank are used, thus achieving miniaturization of the system and high cooling performance by flow rate increase.

It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims. 

1. A liquid circulation system which permits liquid to pass through a component thereof, comprising: an impeller having a plurality of vanes; a wall of the component on which the impeller is mounted and in which an opening section is formed so as to permit the vanes to be disposed; a partition section having a hole at such a position as to face a rotating shaft of the impeller; and a port formed by the wall and the partition section, wherein the liquid passing through the component flows into the port through the hole by the rotation of the impeller.
 2. The liquid circulation system according to claim 1, comprising: a bottom wall for supporting the rotating shaft of the impeller; and electromagnets mounted on the opposite side to the impeller on the bottom wall, wherein the impeller is rotated by the electromagnets and permanent magnets included in the impeller.
 3. The liquid circulation system according to claim 2, wherein the bottom wall includes a liquid sealing member on the same side as the impeller.
 4. A liquid circulation system which permits liquid to pass through a component thereof, comprising: an impeller having a plurality of vanes; an inlet port for permitting liquid to flow into from the outside of the component; and a duct connected with the inlet port and having a hole such at a position as to face the rotating shaft of the impeller, wherein liquid flowing into from the inlet port flows into the inside of the component through a hole of the duct by the rotation of the impeller.
 5. The liquid circulation system according to claim 4, comprising: a bottom wall for supporting the rotating shaft of the impeller; and electromagnets mounted on the opposite side to the impeller on the bottom wall, wherein the impeller is rotated by the electromagnets and permanent magnets included in the impeller.
 6. The liquid circulation system according to claim 5, wherein the bottom wall includes a liquid sealing member on the same side as the impeller.
 7. The liquid circulation system according to claim 4, wherein the liquid passing through the component is a collision jet flow against the inside of the component.
 8. A liquid cooling system for cooling a component with coolant, comprising: the liquid circulation system according to claim 1, wherein the component is the one that performs heat exchange.
 9. A liquid cooling system for cooling a component with coolant, comprising: the liquid circulation system according to claim 1, wherein the component is the one that retains coolant.
 10. A liquid cooling system for cooling a component with coolant, comprising: the liquid circulation system according to claim 4, wherein the component is the one that comes into contact with a heat generating member to cool the heat generating member.
 11. The liquid circulation system according to claim 1, including: a pump section having a bottom wall for supporting the rotating shaft of the impeller and electromagnets mounted on the opposite side to the vanes on the bottom wall, wherein the pump section rotates the impeller by the electromagnets and the permanent magnets included in the impeller.
 12. The liquid circulation system according to claim 4, including: a pump section having a bottom wall for supporting the rotating shaft of the impeller and electromagnets mounted on the opposite side to the vanes on the bottom wall, wherein the pump section rotates the impeller by the electromagnets and the permanent magnets included in the impeller. 